I recently was baffled by why I couldn't play DVDs with xine or mplayer. Then I realized that I had to get an extra component for dvd encryption. (as a former mandrake user, i'm too used to having everything done for me) Anyway, a quick "pacman -S libdvdcss" did the trick.
Now, I have a concern... as a regular user (non-root) I couldn't play dvd's unless I did "chmod o+rw /dev/hdd". I also had to do "chmod o+rw /dev/snd" and "chmod o+rw /dev/sound" (and run alsamixer to unmute my master volume). It works but is it the proper way to do it?
arch default udev setup uses the groups audio and optical,
add your user to the groups
gpasswd -a ylikone audio gpasswd -a ylikone optical
arch + gentoo + initng + python = enlisy